Semiconductor components, such as dice and packages, are typically tested at the wafer level prior to being singulated into separate components. Semiconductor components include patterns of component contacts, such as bond pads, redistribution pads or test pads, which provide electrical connection points for addressing the integrated circuits contained on the components. An interconnect having interconnect contacts can be used to make temporary electrical connections with the component contacts. Test signals are then transmitted through the interconnect contacts and the component contacts, to the integrated circuits contained on the components.
One type of conventional interconnect is a probe card. Probe cards come in several varieties, including needle probe cards and membrane probe cards. A needle probe card, includes a substrate, circuit traces on the substrate, and needle probes soldered to openings in the substrate in electrical communication with circuit traces.
One problem with a conventional needle probe cards is that the planarity and vertical position of the needle probes can vary. These variations can cause inaccuracies in the test results because electrical contact with the component contacts can vary. Continued use of needle probe cards causes wear, deformation and further misalignment of the needle probes.
Membrane probe cards typically include a membrane formed of a thin and flexible dielectric material such as polyimide, and interconnect contacts in the form of metal bumps on the membrane. In general, membrane probe cards are able to compensate for vertical misalignment between the component contacts. However, the manufacturing process for membrane probes is complex and expensive. In addition, support mechanisms for membrane probes are also complicated and can require a large number of moving parts.
Another disadvantage of membrane probe cards is that large contact forces are required to make reliable electrical connections between the metal bumps on the membrane, and the component contacts on the components. These contact forces include a vertical “overdrive” force, and a horizontal “scrubbing” force. These large forces can damage the component contacts and the components. In addition, the metal bumps and the membranes are repeatedly stressed by the large forces, which can cause the membrane to lose its resiliency. Elastomeric members in the support mechanisms can also be compressed and damages with repeated use.
Another type of interconnect for electrically engaging semiconductor components includes semiconductor interconnect contacts having projections for penetrating the component contacts to a limited penetration depth. This type of interconnect is disclosed in U.S. Pat. No. 5,483,741 to Akram et al.; U.S. Pat. No. 5,686,317 to Akram et al., U.S. Pat. No. 5,716,218 to Farnworth et al. and U.S. Pat. No. 6,072,321 to Akram et al.
In view of the deficiencies associated with conventional interconnects, the present invention is directed to an improved interconnect for semiconductor components. The interconnect of the present invention includes semiconductor contacts having an integrally formed spring element. In addition, the present invention is directed to test systems incorporating the interconnect, to test methods performed using the interconnect, and to fabrication methods for fabricating the interconnect.